Photographic material



1946. c. STAUD 2 3 PHOTGRAPHIC MATERAL Filed A ri 15, 1942 3 FHOTOGRAPHC 2 .-5UPFORT CmIL J .STAUD INVENTOR '24 T'TORNE Y Patented Oct. 8, 1946 PHOTO GRAPHIC MATERIAL Cyril J Stand, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application April 15, 1942, Serial No. 439,()0'7 1 Claim. l

This invention relates to a photographic material of the type in which a luminescent layer is positioned between the support and the photographic emulsion and, specifically, it is an improvement over that disclosed in the Patent No. 2,332,038, of Clarence L. A. Wynd and Gerould T, Lane, and is of use in the process of Patent No. 2,322,082 of the sam inventors.

In the process therein described, a differentially luminescent image is printed upon a photographic layer beneath which is a fiuorescent layer from which it is shielded by a removable opaque layer, so that any rays emitted by the luminescent layer during the exposure of th photographic layer do not also affect it. The image is developed by a process removing the opaque layer and the resulting element contains a photographic image and a fluorescent screen which can be used to impress a diiierentially luminescent image upon another photographic element.

The present invention relates to a photographic element in which there is no removable opaque screen but which can be used in the same process,

Referring to the accompanying figure, l indicates a support` 2 a uorescent layer thereon and 3 a sensitive photographic emulsion.

The support i may be a rigid sheet such as steel, alurninum, plywcod or other material. over which is coated a layer 2 containing a material which, when activated by light or X-rays emits rays to which the photographic layer 3 is insensitive. For example, if the layer 3 is an emulsion insensitive to green, the luminescent material in layer 2 may be zinc-ortho-silicate, which when activated by X-rays fiuoresces with a maximum at about 525 mu, in the green region of the spectrum.

The process in which this photographic element is used involves the making of a differentially luminescent image the color of the rays from which are of a wave length to which the photographic layer 3 is sensitive. This image may be made by drawing with an opaque lacquer or pencil upon a fluorescent screen; by drawing With a pencil or lacquer containing a fluorescent material upon a non-fiuorescent sheet; by scriving or engraving in a fluorescent layer, removing the fluorescent material to form a non-fluorescent line or image; or by any other means forming an image which when activated by light, X- rays or other radiant energy is difierentially luminous. The luminescent material may be calcium tungstate as proposed by Lane and Wynd in their application, Serial No. 401959, filed August 22, 1941, now Patent No. 2303342, granted December 1, 1942, or, preferably barium fiuorochloride as described in the copending application of Herbert J. Dietz, Serial No. 431197, filed April 1, 1942 now Patent No. 2,303',917, granted December 1, 1942. The light emitted from this is in the violet and.

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2 ultraviolet region to which ordinary photographic emulsions are highly sensitive.

The sheet carrying the image made as described is placed in contact with my improved photographic element and exposed to X-rays which produce a fiuorescent image, with continuing phosphorescence for a time after activation. The luminescent rays impress a developable latent image in the layer 3. The X-rays also excite the luminescent material in the layer 2, but the rays emitted thereby do not afiect the layer 3.

After development there remains a silver opaque image in the layer 3. This element is placed in contact with a support carrying a green sensitive photographic layer. When th assemled plates are exposed to X-rays the green luminescent rays from the layer 2 afiect the green sensitive layer except where they are intercepted by the opaque silver image.

Since all of the supports are preferably of opaque, nonfrangible material as is necessary when the images are drawings used in making templates or patterns of large size such as are suitable for making large maps and automobile and airplane parts, the final image is positive and also unreversed from right to left with respect to the original luminescent image.

In order to reduce halation, an anti-halation dye may be used in the layer 2. This dye, if not clecolorized cr removed in the processing bath, should transm't the luminescent light but absorb the light to which the layer 3 is sensitive. Examples of dyes transmitting green and abserbing blue and violet not causing serious desensitization are (1) tartrazine and related pyrazolcne dyes (2) simple azo dyes free from nitro or amino groups, such as benzine azo resorcinol or 2-hydroxy-5-l(l-naphthyl azo) -benzaldehyde, or (3) monomethin oXonol dyes, such as bis-[1- sulfophenyl-3-methy1-5-pyrazolone-(4)l methine oxonol.

The first sheet carrying the image may be exposed to X-rays while out of contact with my improved plate and then at once moved into contact with it, the exposure taking place entirely by phosphorescent light. Since this exposure is of the order of several minutes, there will be no appreciable fogging during the short time required to bring th sheets into contact.

Having thus described my invention, what I claim as new and desire to be secured by Letters Patent of the United States is:

A photographic element comprising a rigid, opaque, non-frangible support, a layer of luminescent material thereon which emits green light when subjected to X-rays and a photographically sensitive layer nsensitive to green light over said luminescent layer,

CYRIL J. STAUD; 

